The "WebCompiler.CompilerBuildTask" task could not be loaded from the assembly

[ecoffman]

Installed product versions

• Visual Studio: VS Enterprise 2017
• This extension: 1.11.326

Description

The "WebCompiler.CompilerBuildTask" task could not be loaded from the assembly

Steps to recreate

dotnet restore .\src
dotnet publish "$scriptPath\src" -c Release -r win10-x64 -o "$scriptPath\build"

Current behavior

C:\Users\eric.nuget\packages\buildwebcompiler\1.11.326\build\BuildWebCompiler.targets(15,9): error MSB4062: The "WebCompiler.CompilerBuildTask" task could not be loaded from the assembly C:\Users\eric.nuget\packages\buildwebcompiler\1.11.326\build..\tools\WebCompiler.exe. Could not load file or assembly 'Microsoft.Build.Utilities.v4.0, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified. Confirm that the declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. [C:\develop\pattnc\src\pattnc\pattnc.csproj]

Expected behavior

Compile SCSS into CSS.

[tjdavis1111]

Installed Products

• Microsoft Visual Studio Community 2017 - Version 15.5.2
• Web Compiler - 1.11.326

Steps to Recreate
dotnet ef migrations add "Identity" -o "Data\Migrations" -v

Current Behavior
C:\Users\davistj.nuget\packages\buildwebcompiler\1.11.326\build\BuildWebCompiler.targets(15,9): error MSB4062: The "WebCompiler.CompilerBuildTask" task could not be loaded from the assembly C:\Users\davistj.nuget\packages\buildwebcompiler\1.11.326\build..\tools\WebCompiler.exe. Could not load file or assembly 'Microsoft.Build.Utilities.v4.0, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified. Confirm that the declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. [C:\LNGOAKTFSA001\0_Internal\TestMakerFree\TestMakerFreeWebApp\TestMakerFreeWebApp.csproj]

Expected Behavior
Compiled into Migration

[tjdavis1111]

Here's how I resolved:

1.) Updated "Microsoft.Build.Utilities.Core" to V15.5.180

2.) Add the following to .csproj
<PackageReference Include="Microsoft.Build.Utilities.Core" Version="15.5.180" />

3.) Rebuilt the solution

4.) Ran "dotnet ef migrations add "Identity" -o "Data\Migrations" -v"

[JimiSweden]

My solution:
use BuildWebCompiler version 1.11.375
do a forced restore av packages (this was a crucial part)

cmd lines:
dotnet add package version 1.11.375
dotnet restore -- force

.csproj
<PackageReference Include="BuildWebCompiler" Version="1.11.375" />

Problem:
I had a similar problem (the same error) on our buildserver, build was successfull in VS 2017. The same error occurred locally when using cmd "dotnet build"
I followed suggestion above and added "Microsoft.Build.Utilities.Core" with no success.

Related problem and solution:
I also use BuildBundlerMinifier and with version 2.8.391 I got the build error message "Bundler & Minifier error 0: Could not load file or assembly 'NUglify, Version=1.5.10.0"
as pointed out in madskristensen/BundlerMinifier#353 (comment) I downgraded to version 2.6.362

<PackageReference Include="BuildBundlerMinifier" Version="2.6.362" />

Note: if you use bootstrap 4 read the issue linked above as there is a bug in 2.6.362 and a workaround for build steps are pointed out by axelheer

[motivity-chris]

i was unable to work around the problem by pinning the aforementioned versions, so i addressed the problem directly in PR #437, which ensures that the _WebCompilerTaskAssembly paths defined in build/BuildWebCompiler.targets are always relative that file (as they were intended to be).